In-cell touch type display device, touch circuit, display driver, and in-cell touch type display device driving method

ABSTRACT

The present disclosure provides an in-cell touch type display device, a touch circuit, a display driver, and an in-cell touch type display device driving method, which can not only sense the position of a touch generated by the user, but also sense the touch force, with which the user presses the screen during the touch, in order to provide various functions in various types.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from and the benefit under 35 U.S.C.§119(a) of Republic of Korea Patent Application No. 10-2015-0127298,filed on Sep. 8, 2015, which is hereby incorporated by reference for allpurposes as if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present embodiments relate to an in-cell touch type display device,a touch circuit, a display driver, and an in-cell touch type displaydevice driving method.

2. Description of the Prior Art

Development of information-oriented societies has been increasingvarious kinds of demands for display devices, and various types ofdisplay devices have been used, such as a liquid crystal display device,a plasma display device, and an organic light-emitting display device.

Among the display devices, furthermore, mobile devices, such as smartphones and tablets, and medium/large-sized devices, such as smarttelevisions, provide touch-type input processing according to userconvenience, device characteristics, and the like.

Display devices capable of such touch input processing are evolving toprovide more diversified functions, and user demands are also becomingmore diversified.

However, the types of touch type display devices currently available inthe market senses only the user's touch position (touch coordinate) byprocessing relevant input from the sensed touch position. Further, thetouch type display devices has limitations in providing many functionsof various kinds and satisfaction of various user demands.

SUMMARY

Embodiments relate to an in-cell touch type display device comprising aplurality of first electrodes, at least one second electrode, and atouch circuit. The plurality of first electrodes are embedded in adisplay panel. At least one second electrode is placed outside thedisplay panel and capacitively coupled to each of the first electrodes.The touch circuit is coupled to the first electrodes and the at leastone second electrode. The touch circuit applies a first voltage signalto each of the first electrodes, applies a second voltage signal to theat least one second electrode, and detects touch force on the displaypanel by processing a sensing signal representing a voltage level ateach of the first electrode, responsive to applying the first voltagesignal and the second voltage signal.

In one embodiment, the first signal and the second signal are appliedduring a touch driving period within a frame period.

In one embodiment, the first and second signals have an identical phasebut different voltage levels.

In one embodiment, the first and second signals have a phase differenceof 180 degrees and have different voltage levels.

In one embodiment, the touch circuit further determines a coordinate ofa touch by processing sensing signals from the first electrodes.

In one embodiment, the sensing signal is of a first voltage levelresponsive to the display panel receiving a touch of a first touch forceand the sensing signal is of a second voltage level responsive to thedisplay panel receiving a touch of a second touch force weaker than thefirst touch force, the first voltage level higher than the secondvoltage level.

In one embodiment, the touch circuit determines the touch as a firsttype of touch responsive to a voltage level of the sensing signal notexceeding a reference voltage and determine the touch as a second typeof touch responsive to the voltage level of the sensing signal exceedingthe reference voltage.

In one embodiment, each of the first electrodes and the at least onesecond electrode are separated by a distance that changes according tomagnitude of touch force on the display panel, the change in thedistance causing change in the sensing signal.

In one embodiment, air or dielectric material is between the firstelectrodes and the at least one second electrode.

In one embodiment, the in-cell touch type display device furtherincludes a structure configured to mount the display panel. The at leastone second electrode is placed beneath or inside the structure.

In one embodiment, the in-cell touch type display device furtherincludes a gap structure unit setting a distance between the firstelectrodes and the at least one second electrode when the touch force isnot applied to the display panel. The distance changing responsive thetouch force applied to the display panel.

In one embodiment, the gap structure unit includes a base plate on whichthe at least one second electrode is mounted; and a spacer elasticpattern between edges of an upper surface of the at least one secondelectrode and edges of a rear surface of a lower structure.

In one embodiment, the gap structure unit includes a base plate on whichthe at least one second electrode is mounted; and an elastic sheetbetween an upper surface of the at least one second electrode and a rearsurface of a lower structure.

In one embodiment, the gap structure unit includes an upper film on arear surface of a lower structure; a lower film facing the upper film;and a bonding agent bonding edges of a rear surface of the upper film toan upper surface of the lower film.

In one embodiment, the gap structure unit includes an elastic filmbetween an upper surface of the at least one second electrode and a rearsurface of a lower structure.

In one embodiment, the gap structure unit includes an inner patternembedded in a lower structure.

In one embodiment, the lower structure is a back light unit of thedisplay panel.

In one embodiment, the first electrodes are applied with a commonvoltage during a display driving period of the frame period.

In one embodiment, the touch circuit is included inside a data driverfor generating signals for operating pixels in the display panel.

In one embodiment, the touch circuit comprises a first switch and asecond switch. The first switch is turned on or off to selectivelyconnect each of the first electrodes to a first reference voltage. Thesecond switch is turned on or off to selectively connect each of thefirst electrode to a second reference voltage lower than the firstreference voltage. The first signal changes between the first referencevoltage and the second reference voltage.

In one embodiment, the touch circuit further includes a third switch anda fourth switch. The third switch is turned on or off to selectivelyconnect the at least one second electrode to a third reference voltage.The fourth switch is turned on or off to selectively connect the atleast one second electrode to a fourth reference voltage lower than thethird reference voltage. The second signal changing between the thirdreference voltage and the fourth reference voltage.

In one embodiment, the touch circuit includes a signal path, a resistor,a capacitor, an operational amplifier, an analog-to-digital converterand a processor. The signal path is connected to each of the firstelectrodes. The resistor is connected to the signal path. The capacitorhas a first node connected to the resistor. The operational amplifierhas an inverted input connected to the resistor and an output connectedto a second node of the capacitor. The analog-to-digital converterreceives an output signal from the output of the operational amplifierand convert the output signal to a digital signal. The processorprocesses the digital signal to detect the touch force.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a conceptual diagram illustrating a schematic configuration ofa touch system of an in-cell touch type display device according to oneembodiment.

FIG. 2 is a timing diagram illustrating driving periods of an in-celltouch type display device according to one embodiments.

FIG. 3 is a diagram illustrating the structure of a touch systemaccording to one embodiment.

FIG. 4 is a diagram illustrating an equivalent circuit diagram of thein-cell touch type display when providing driving signal to electrodes,according to one embodiment.

FIG. 5 is a timing diagram illustrating relationships between signalsfor driving first and second electrodes in a touch system according toone embodiment.

FIG. 6 is a timing diagram illustrating relationships between signalsfor driving first and second electrodes in a touch system according toanother embodiment.

FIG. 7 is a circuit diagram illustrating an example of a touch circuitfor providing voltage signals to the electrodes and sensing charges inthe electrodes, according to one embodiment.

FIG. 8 is a diagram illustrating the amplitude of a received signalbased on a force touch according to one embodiment.

FIG. 9A is a graph illustrating the amplitude distribution of receivedsignals based on a soft touch according to the present embodiments.

FIG. 9B is a graph illustrating the amplitude distribution of receivedsignals based on a hard touch according to the present embodiments.

FIG. 10 is an schematic exploded view of a touch system according to oneembodiment.

FIG. 11 is a schematic exploded view of an in-cell touch type displaydevice according to one embodiment.

FIG. 12 is a cross-sectional diagram of an in-cell touch type displaydevice according to another embodiment.

FIG. 13 through FIG. 17 are cross-sectional diagrams illustrating gapstructure units of touch systems according to embodiments.

FIG. 18 is a block diagram of a touch circuit according to oneembodiment.

FIG. 19 through FIG. 21 are plan views illustrating in-cell touch typedisplay devices and touch circuits according to embodiments.

FIG. 22 is a block diagram of a display driver according to oneembodiment.

FIG. 23 is a diagram illustrating using data lines to connect a datadriving circuit in a display driver with first electrodes, according toone embodiment.

FIG. 24 is a conceptual diagram illustrating applying voltage signals toelectrodes, according to one embodiment.

FIG. 25 is a flowchart of a method for driving an in-cell touch typedisplay device, according to one embodiment.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Hereinafter, embodiments of the present invention will be described indetail with reference to the exemplary drawings. In designating elementsof the drawings by reference numerals, the same elements will bedesignated by the same reference numerals although they are shown indifferent drawings. Further, in the following description of the presentinvention, a detailed description of known functions and configurationsincorporated herein will be omitted when it may make the subject matterof the present invention rather unclear.

In addition, terms, such as first, second, A, B, (a), (b) or the likemay be used herein when describing components of the present invention.Each of these terminologies is not used to define an essence, order orsequence of a corresponding component but used merely to distinguish thecorresponding component from other component(s). In the case that it isdescribed that a certain structural element “is connected to”, “iscoupled to”, or “is in contact with” another structural element, itshould be interpreted that another structural element may be connectedto”, “be coupled to”, or “be in contact with” the structural elements aswell as that the certain structural element

FIG. 1 is a diagram illustrating a schematic configuration of a touchsystem 100 of an in-cell touch type display device according to oneembodiment. Referring to FIG. 1, the in-cell touch type display deviceincludes a touch system 100 for sensing a touch by a pointer such as afinger or a pen. The touch system 100 not only senses whether a touchhas occurred and the coordinate of the touch, but also force of thetouch (hereinafter referred to as “touch force”) applied by the pointerduring the touch.

The touch system 100 may include multiple first electrodes E1 fordetecting a coordinate of the touch, a second electrode E2 for sensingthe touch force of the touch and a touch circuit 120. The touch circuit120 sends driving signals to the multiple first electrodes E1 and thesecond electrode E2 and also senses occurrence of a touch, thecoordinate of the touch and the magnitude of the touch force.

The multiple first electrodes E1, which correspond to touch sensors fordetermining whether a touch has occurred or not and to obtain thecoordinate of the touch, may be arranged on a touch screen panelseparate from the display panel 110 or be embedded and arranged in thedisplay panel 110.

When the multiple first electrodes E1 are embedded and arranged in thedisplay panel 110 as described above, the display panel 110 can bereferred to as a “touch screen panel-integrated display panel” in whichmultiple first electrodes D1 are embedded. The in-cell touch typedisplay device includes an “in-cell type touch screen panel.”

On the other hand, the second electrode E2 for sensing the touch forcemay be positioned outside of the display panel 110 (for example, lowerportion, upper portion, or side surface).

Driving signals for the multiple first electrodes E1 used for sensing atouch and detecting the coordinate of the touch, and driving signals forthe second electrode E2 for sensing a touch force of the touch may beapplied during the same process. Specifically, the touch circuit 120 ofthe touch system 100 may sequentially apply a first electrode drivingsignal DS1 to the multiple first electrodes E1 and also apply a secondelectrode driving signal DS2 to the second electrode E2, during a singletouch driving period. That is, the multiple first electrodes E1 and thesecond electrode E2 are driven together during a single touch drivingperiod.

The touch system 100, the multiple first electrodes E1 embedded in thedisplay panel 110, and the second electrode E2 positioned outside thedisplay panel 110, may be collectively referred to as a “force sensor.”In addition, the multiple first electrodes E1 embedded in the displaypanel 110 may be referred to as “touch sensors” or “touch electrodes.”

As described above, the touch system 100 performs first electrodedriving and second electrode driving in the same touch driving process(touch driving period); and therefore, can perform sensing related tooccurrence of a touch, the coordinate of the touch and touch forcesensing within a shorter period of time compared with a case in whichthe first electrode driving and the second electrode driving areperformed separately in different touch driving periods.

On the other hand, the touch system 100 according to the presentembodiments may further include a second electrode driving signalgeneration unit 130 for generating a second electrode driving signalDS2, which corresponds to the first electrode driving signal DS1.

The second electrode driving signal generation unit 130 may be includedoutside the touch circuit 120 or may be included inside the touchcircuit 120.

The second electrode driving signal generation unit 130 may beimplemented in various types of circuit and, for example, may beimplemented to include a level shifter or, in some cases, may include aphase converter.

The second electrode driving signal generation unit 130 can generate asecond electrode driving signal DS2 by shifting the voltage levelrelated to a first electrode driving signal DS1 generated by the touchcircuit 120 or by a different device. The first second electrode drivingsignal DS2 may, for example, be generated by shifting the phase of thefirst electrode driving signal DS1.

A touch driving period, in which first electrode driving and secondelectrode driving are conducted together, may proceed together with adisplay driving period for image display, or may be time-divided withthe display driving period and proceed between respective displaydriving periods.

FIG. 2 illustrates time-divisional operation of display driving in adisplay driving period and and touch driving in a touch driving period,according to one embodiment. Referring to FIG. 2, the in-cell touch typedisplay device according to embodiments may time-divide one frame periodinto a display driving period and a touch driving period. One frameperiod refers to a period for displaying a frame of image on the displaypanel. During the touch driving period, both first electrode driving andsecond electrode driving may be performed.

Therefore, during the touch driving period, a first electrode drivingsignal DS1 may be applied to the multiple first electrodes E1 and asecond electrode driving signal DS2 may be applied to the secondelectrode E2.

On the other hand, the multiple first electrodes E1 embedded andarranged in the display panel 110 may be dedicated electrodes for touchsensing, or may be display driving electrodes also used for displayingimages on the display panel 110. In one embodiment, the multiple firstelectrodes E1 may be common voltage electrodes embedded and arranged inthe display panel 110 for receiving a common voltage Vcom during thedisplay driving period. In such embodiment, a common voltage may beapplied to all of the multiple first electrodes E1 as a display drivingvoltage during display driving, and a first electrode driving signal DS1may be sequentially applied to each of the multiple first electrodes E1during touch driving.

As described above, the multiple first electrodes E1 are mode sharingelectrodes, which may also be used as display driving electrodes, makingit unnecessary to separately form electrodes for two different uses(i.e., display and touch sense) on the display panel 110. This may makethe panel design easy and the panel structure simple.

A structure for sensing a touch coordinate and a touch force by thetouch system 100 according to embodiments and a touch driving methodwill hereinafter be described in more detail.

FIG. 3 is a schematic diagram illustrating the structure of the touchsystem 100 according to one embodiment. Referring to FIG. 3, the touchsystem 100 does not use a dedicated pressure sensor for pressuresensing, as in the case of an existing pressure sensing touch sensors,but instead uses a second electrode E2 outside the display panel 110 inconjunction with multiple first electrodes E1 embedded in the displaypanel 110 for sensing touch force. The multiple first electrodes E1 arealso used for sending touch coordinate.

That is, sensing of the touch force can be conducted by driving multiplefirst electrodes E1 and a second electrode E2 together.

Referring to FIG. 3, during a touch driving period, a first electrodedriving signal DS1 is applied to a first electrode E1. If a secondelectrode driving signal DS2 is applied to the second electrode E2, afirst capacitance C1 is formed between a pointer (e.g., a finger) andthe first electrode E1 while a second capacitance C2 is formed betweenthe first electrode E1 and the second electrode E2.

The touch circuit 120, for example, may calculate a touch coordinate andsense a touch force based on the change of the first capacitance C1 andthe second capacitance C2.

Referring to FIG. 3, second capacitance C2 is formed between the firstelectrode E1 and the second electrode E2. The second capacitance C2 is afunction of a gap G between the first electrode E1 and the secondelectrode E2. The gap G existing between the first electrode E1 and thesecond E2 may change according to the magnitude of touch force on theupper portion of the display panel 110.

The change in the gap G may vary depending on the position. That is, thechange of gap G when the touch force is applied to the center point ofthe second electrode E2 may be larger than the change of gap G whentouch force is applied at the edge points of the second electrode E2 andthe multiple first electrodes E1. This is particularly true when theedge portions of the second electrode E2 are bonded or coupled to aperipheral structure.

When the change of the gap G occurs as a result of a touch force, thesecond capacitance C2 between the first electrode E1 and the secondelectrode E2 changes accordingly, and the touch force can be sensed baseon the degree of change in the second capacitance C2.

In such embodiments, two kinds of sensing (i.e., touch position sensingand touch force sensing) can be performed efficiently by using the samestructure.

The above-mentioned gap G existing between the multiple first electrodesE1 and the second electrode E2 may be an air gap or a gap withdielectric substance inbetween.

FIG. 4 is a schematic illustration of the structure of the touch system100, according to one embodiment. 3. Referring to FIG. 4, during a touchdriving period, a first electrode driving signal DS1 is applied to afirst electrode E1. If a second electrode driving signal DS2 is appliedto the second electrode E2 while the the first electrode driving signalDS1 is applied, a first capacitance C1 is formed between a pointer(e.g., a finger) and the first electrode E1 while a second capacitanceC2 is formed between the first electrode E1 and the second electrode E2.

Electrical charge Q1 in the capacitor between the pointer and the firstelectrode E1 during such touch driving is determined by the firstcapacitance C1 and the voltage V1 of the first electrode driving signalDS1.

In addition, electrical charge Q2 that charges a capacitor between thefirst electrode E1 and the second electrode E2 may be determined by thesecond capacitance C2, the voltage V1 of the first electrode drivingsignal DS1, and the voltage V2 of the second electrode driving signalDS2.

Particularly, the electrical charge Q1, which charges the capacitorbetween the pointer and the first electrode E1, and the amount ofelectrical charge Q2, which charges the capacitor between the firstelectrode E1 and the second electrode E2, during touch driving, may beexpressed by equation (1) below:Q1=C1×V1; Q2=C2×(V1−V2)  Equation (1)

Characteristics of signals DS1 and DS2 used during the above-mentionedtouch driving (first electrode driving and second electrode driving) arehereinafter be described.

FIG. 5 is a timing diagram illustrating a first electrode driving signalDS1 for first electrode driving and a second electrode driving signalDS2 for second electrode driving in connection with a touch system 100according to one embodiment. FIG. 6 is a diagram illustrating a firstelectrode driving signal DS1 for first electrode driving and a secondelectrode driving signal DS2 for second electrode driving in connectionwith a touch system 100 according to another embodiment.

As illustrated in FIG. 5, the second electrode driving signal DS2 andthe first electrode driving signal DS1 may have the same phase. In thiscase, the second electrode driving signal DS2 and the first electrodedriving signal DS1 have an equiphase (same phase) relationship.

By using a second electrode driving signal DS2 and a first electrodedriving signal DS1 having the same phase, efficient touch driving(second electrode driving and first electrode driving) and efficientsensing (touch force sensing and touch coordinate sensing) can beperformed. In addition, two kinds of signals for touch driving, i.e.,the second electrode driving signal DS2 and the first electrode drivingsignal DS1, can be generated easily.

On the other hand, referring to FIG. 5, the second electrode drivingsignal DS2 may have a voltage level higher than the voltage of the firstelectrode driving signal DS1. That is, the voltage V2 of the secondelectrode driving signal DS2 may be higher than the voltage V1 of thefirst electrode driving signal DS1. When the voltage V2 of the secondelectrode driving signal DS2 is higher than the voltage V1 of the firstelectrode driving signal DS1, the electrical charge Q2 in the capacitorbetween the first electrode E1 and the second electrode E2 has anegative (−) value.

In this regard, the signal received from the first electrode E1 is asignal corresponding to the combined amount of electrical charges Q1+Q2.As the electrical charge Q2 has a negative (−) value, Q1+Q2 becomessmaller than Q1; and as a result, the voltage level of a sensing signalreceived from the first electrode E1 is reduced.

Therefore, if (i) the voltage V2 of the second electrode driving signalDS2 is higher than the voltage V1 of the first electrode driving signalDS1 and (ii) the second electrode driving signal DS2 and the firstelectrode driving signal DS1 have an equiphase relationship, the voltagelevel of the signal received from the first electrode E1 becomesnegative (−) with reference to the baseline, which enables accuratedistinction between a soft touch (i.e., when the pressing force does notexist or is equal to or below a predetermined level) and a force touch(i.e., when the pressing force exists or exceeds the predeterminedlevel).

As illustrated in FIG. 6, the second electrode driving signal DS2 andthe first electrode driving signal DS1 may have a phase difference of180 degrees. In such embodiment, the second electrode driving signal DS2and the first electrode driving signal DS1 have a reverse-phaserelationship.

When a second electrode driving signal DS2 and a first electrode drivingsignal DS1 having a reverse-phase relationship as described withreference to FIG. 6 are used, the voltage difference (V1−V2) between thevoltage V1 of the first electrode driving signal DS1 and the voltage V2of the second electrode driving signal DS2 increases to a positive value(+). When an appropriate sensing scheme is implemented, use of thesecond electrode driving signal DS2 and the first electrode drivingsignal DS1, which have a reverse-phase relationship, may be efficient.

An example of an internal circuit configuration of a touch circuit 120,which is configured for the above-mentioned touch driving and sensing ofa touch coordinate and a touch force therethrough, will hereinafter bedescribed.

FIG. 7 is a circuit diagram illustrating an example of a touch circuit120 according to one embodiment. As illustrated in FIG. 7, the touchcircuit 120 may include a first electrode driving signal supply unit 710configured to supply a first electrode driving signal DS1 as a modulatedsignal having a high voltage level V1 and a low voltage level V0, byturning on or off two switches SW1 and SW10. A second electrode drivingsignal supply unit 720 supplies a second electrode driving signal DS2 asa modulated signal having a high voltage level V2 and a low voltagelevel V0 by turning on or off two switches SW2 and SW20. The touchcircuit also includes an integrator 730 with an operation amplifierOP-AMP, a capacitor C, a resistor R, an analog-digital converter ADCconfigured to convert the output value from the integrator 730 to adigital value, and a processor 740 configured to perform touchcoordinate calculation, touch force recognition, and the like on thebasis of the digital value output from the analog-digital converter ADC.

In other embodiments, at least one of the analog-digital converter ADC,and the processor 740 may be positioned outside the touch circuit 120.

The circuit configuration of the touch circuit 120 illustrated in FIG. 7is only an example for convenience of description, and may beimplemented in various other forms. For example, a multiplexer betweenthe touch circuit 120 and a plurality of first electrodes E1 forsequentially process signals from the first electrodes E1 is omittedherein for the sake of brevity.

As illustrated in FIG. 7, the touch circuit 120 may sequentially apply afirst electrode driving signal DS1 to multiple first electrodes E1,apply a second electrode driving signal DS2 to a second electrode E2,and sense the amount of charge (or voltage level) resulting from thechange in size of the gap G between the multiple first electrodes E1 andthe second electrode E2 during touch driving based on signals receivedfrom each of the first electrodes E1 to recognize the touch force.

When the pointer is made of a non-conductive material, the touch circuit120 can sense only a touch force on the basis of signals received fromthe multiple first electrodes E1. However, when the pointer is made of aconductive material, the touch circuit 120 can additionally detect thecoordinate of the touch based on the signals received from the multipleelectrodes E1.

The signals received from one of the multiple first electrode E1correspond to the combined electrical charges Q1+Q2. The combinedelectrical charges Q1+Q2 is used to charge the capacitor C inside theintegrator 730 and is output from the integrator 730 as a sensingvoltage value Vsen.

The analog-digital converter ADC converts the sensing voltage value Vsento a digital value.

As the multiplexer (not shown) sequentially couples each of the firstdelectrodes E1 to the integration unit 120, Vsen value for each of thefirst electrodes E1 are obtained from the integration unit 730 and thenconverted into digital values. The processor 740 stores the digitalversion of Vsens values. Based on the distribution of the digitalversion of Vsens values, the processor 740 may calculate a touchcoordinate and also determine the magnitude of the touch force. That is,the processor 740 performs touch coordinate calculation and force touchdetection using the same signal. This enables two kinds of sensing(touch sensing and touch force sensing) to be performed quickly andefficiently.

When touch force has been detected, an application or a functioncorresponding to the touch force may be executed on an electronic devicemounted with the touch screen. The touch circuit 120 may also sense thecharge (or voltage), which follows the change in size of the gap Gbetween the multiple first electrodes E1 and the second electrode E2,and determine the strength of the touch force according to the charge(or voltage level). According to the above description, it is possibleto determine not only whether there was force applied during a touchforce but also the strength of the touch force applied by the user.

In this regard, when the size of a touch force is determined, anapplication or a function, which has been predetermined so as tocorrespond to the grasped size of the touch force, may be differentiatedand executed.

Characteristics of received signals generated differently depending onwhether the touch was a soft touch or a force touch at a touch system100 is hereinafter described.

FIG. 8 is a diagram illustrating the amplitude of a received signalresulting from a soft touch, and the amplitude of a received signal,which results from a force touch, in connection with a touch system 100according to one embodiment. FIGS. 9A and 9B are diagrams illustratingthe amplitude distribution of a received signal resulting from a softtouch, and the amplitude of a received signal resulting from a forcetouch according to one embodiment.

Referring to FIG. 8, the signal amplitude of a signal received from thefirst electrode E1 can be confirmed from a digital value output from theanalog-digital converter ADC.

Referring to FIG. 8 and FIG. 9A, when there is no pressing force or thepressing force is equal to or less than a predetermined level, a digitalvalue output from the analog-digital converter ADC has a positive (+)value compared to a digital value output from the analog-digitalconverter ADC when there is no touch at all (baseline). In FIG. 9A, Xaxis and Y axis indicate coordinates of the first electrodes E1 while Zaxis represent digital value output from the ADC at an electrode E1 ofX, Y coordinate. As illustrated in FIG. 9A, the digital value outputfrom the analog-digital converter ADC when a soft touch has occurred hasa peak in an area corresponding to the position of the correspondingfirst electrode E1 where the soft touch has occurred.

Referring to FIG. 8, assuming that the second electrode driving signalDS2 and the first electrode driving signal DS1 have an equiphaserelationship, when a pressing force exists or exceeds a predeterminedlevel, a digital value output from the analog-digital converter ADC hasa negative (−) value compared to a digital value output from theanalog-digital converter ADC when there is no touch at all (baseline).As illustrated in FIG. 9B, the second electrode E2 has the shape of abulk plate outside the display panel 110 so that, the size (signalamplitude) of a digital value output from the analog-digital converterADC, when a force touch occurs, has a distribution having the overallsignal amplitude increasing in the negative direction (−), withreference to the baseline.

The stronger the touch force becomes, the larger the change in size ofthe gap G between the multiple first electrodes E1 and the secondelectrode E2 becomes; therefore, the digital value output from theanalog-digital converter ADC has decreases further in the negativedirection (−), with reference to a digital value output from thedigital-analog converter ADC when there is no touch at all (baseline).That is, the absolute amplitude of the digital version of Vsensincreases in proportion to the amplitude of the force touch.

In summary, signals received from the multiple first electrodes E1,respectively, when the touch is a soft touch and signals received fromthe multiple first electrodes E1, respectively, when the touch is aforce touch may be signals in opposite directions with reference tosignals received from the multiple first electrodes E1, respectively,when there is no touch.

That is, signals received from the multiple first electrodes E1,respectively, when the touch is a soft touch have signal amplitudeslarger than those of baseline signals produced when there is no touch;and signals received from the multiple first electrodes E1,respectively, when the touch is a force touch have signal amplitudessmaller than those of the baseline signals.

Assuming that the second electrode driving signal DS2 and the firstelectrode driving signal DS1 have an equiphase relationship, the amountof charging Q1+Q2 (Q2≠0) sensed when the touch is a force touch, or avoltage corresponding thereto, may be smaller than the amount ofcharging Q1+Q2=Q1 (Q2=0) sensed when the touch is a soft touch, or avoltage corresponding thereto. In this regard, Q1 and Q2 may be theamount of electrical charges for charging or the amount of change in theamount of electrical charges for charging.

In addition, assuming that the second electrode driving signal DS2 andthe first electrode driving signal DS1 have an equiphase relationship,the electrical charge or voltage sensed when the touch is a force touchmay be smaller than the base amount of charging or base voltage sensedwhen there is no touch.

As described above, with reference to signals received from the multiplefirst electrodes E1, respectively, when there is no touch, signalsreceived from the multiple first electrodes E1, respectively, when thetouch is a soft touch are signals in the positive (+) direction (ornegative (−) direction); signals received from the multiple firstelectrodes E1, respectively, when the touch is a force touch are signalsin the negative (−) direction (or positive (+) direction); the amount ofcharging Q1+Q2 sensed when the touch is a force touch, or a voltagecorresponding thereto, is smaller than the amount of charging Q1 sensedwhen the touch is a soft touch, or a voltage corresponding thereto(Q1+Q2<Q1); therefore, an accurate distinction can be made between asoft touch, i.e. the pressing force does not exist or is equal to orless than a predetermined level, and a force touch, i.e. the pressingforce exists or exceeds the predetermined level.

Referring to FIG. 8, assuming that the second electrode driving signalDS2 and the first electrode driving signal DS1 have a reverse-phaserelationship, a digital value output from the analog-digital converterADC when a pressing force exists or exceeds a predetermined level, i.e.when a force touch has occurred, has a value in the positive (+)direction, with reference to a digital value output from theanalog-digital converter ADC when there is no touch at all (baseline),and has a value larger than a digital value output from theanalog-digital converter ADC when the pressing force does not exist oris equal to or less than the predetermined level, i.e., when a softtouch has occurred.

Assuming that the second electrode driving signal DS2 and the firstelectrode driving signal DS1 have a reverse-phase relationship, thecharge Q1+Q2 (Q2>0) sensed when the touch is a force touch, or a voltagecorresponding thereto, may be larger than the amount of chargingQ1+Q2=Q1 (Q2=0) sensed when the touch is a soft touch, or a voltagecorresponding thereto.

Use of the above-mentioned relationship makes it possible to efficientlydistinguish between a soft touch and a force touch, in the case ofconducting touch driving (second electrode driving and first electrodedriving) using a second electrode driving signal DS2 and a firstelectrode driving signal DS1, which have a reverse-phase relationship.

On the other hand, the touch system 100 has a structure that enablessensing of a touch force, and an example of the structure for touchforce sensing will hereinafter be described.

FIG. 10 is a diagram schematically illustrating a touch system 100according to the present embodiments. Referring to FIG. 10, the touchsystem 100 includes multiple first electrodes E1 arranged on a displaypanel 110, a second electrode E2 positioned outside the display panel110, and the like.

In order to sense a touch force, a gap G variable according to a forcetouch is provided between the multiple first electrodes E1 and thesecond electrode E2.

The touch system 100 may include a gap structure unit 1000, which makesa gap G between the multiple first electrodes E1 and the secondelectrode E2, and which enables a change in size of the gap G accordingto touch force. Such a gap structure unit 1000 can enable sensing of atouch force.

FIG. 11 is a diagram illustrating of an in-cell touch type displaydevice according to one embodiment. Referring to FIG. 11, in connectionwith an in-cell touch type display device according to embodiments, thedisplay panel 110 may include a first substrate 1110, on which a TFT(Thin Film Transistor) and the like are arranged, and a second substrate1120, on which a CF (Color Filter) and the like are arranged.Furthermore, the first substrate 1110 may have a driving chip 1130mounted, bonded, or connected to an edge portion (non-active area)thereof.

The driving chip 1130 may be a chip that implements a touch circuit 120or a data driving chip, and in some cases, may also be a display drivingchip including a touch circuit 120, a data driving circuit, and thelike.

Referring to FIG. 11, a lower structure 1100 may be positioned beneaththe display panel 110. A gap structure unit 1000 may be positionedbeneath or inside the lower structure 1100. The second electrode E2 maybe included beneath or inside the gap structure unit 1000. Accordingly,the second electrode E2 may be positioned beneath or inside the lowerstructure 1100 of the display panel 110.

Variously designing the position of the second electrode E2, theposition of the gap structure unit 1000, or the like, as describedabove, can implement a touch system adapted to the design structure ofthe display panel 110 and the in-cell touch type display device.

It will be assumed, hereinafter, that the in-cell touch type displaydevice according to the present embodiments is a liquid crystal displaydevice, and various types of gap structure units 1000 that can beapplied to the liquid crystal display device will be described. In thisregard, the positions of first electrodes E1 and a second electrode E2,which are included in the liquid crystal display device, will now bedescribed briefly.

FIG. 12 is a diagram illustrating a different structure of an in-celltouch type display device 100 according to the present embodiments. Thevertical positions of multiple first electrodes E1, a second electrodeE2, and a lower structure 1100 are illustrated in FIG. 12. The displaypanel 110 includes a first polarization plate 1210, a first substrate1110, multiple first electrodes E1, a second substrate 1120, a secondpolarization plate 12220, and the like. A bonding layer 1230 and anupper cover 1240 are positioned on the display panel 110. A lowerstructure 1100 is positioned beneath the display panel 110.

The lower structure 1100 may be a structure already existing in thein-cell touch type display device, or a structure separately providedfor the second electrode E2. The lower structure 1100, for example, maybe a back light unit, a back cover, or the like of the liquid crystaldisplay device. Besides, any structure is acceptable as long as it doesnot interfere with the electric field generated from the firstelectrodes E1 such that a capacitor can be formed between the firstelectrodes E1 and the second electrode E2.

Positioning the second electrode E2 beneath or inside the lowerstructure 1100, which corresponds to a back light unit, as describedabove, enable implementation of a touch system 100 for an liquid crystaldisplay device.

On the other hand, in the case of a liquid crystal display device, alayer of material such as silver (Ag), a reflection plate, a transparentelectrode layer, and the like is absent to form a second capacitance C2between the first electrodes E1 and the second electrode E2.

Various examples of gap structure units 1000 will hereinafter bedescribed. FIG. 13 to FIG. 17 are diagrams illustrating examples of agap structure unit 1000 of a touch system 100 according to the presentembodiments.

Referring to FIG. 13, the gap structure unit 1000 may include a baseplate 1310 made of a substrate or a film, a spacer elastic pattern 1320positioned between the upper surface edge of a second electrode E2,which is positioned on the base plate 1310, and the rear surface edge ofa lower structure 1100, and the like.

The spacer elastic pattern 1320 may be attached, bonded, or coated onthe rear surface of the lower structure 1100. The spacer elastic pattern1320 is made of an elastic material.

Referring to FIG. 13, when a force touch occurs, the upper cover 1240,the display panel 110, the lower structure 1100, and the like receive adownward force. Accordingly, the touch force may change the size of thegap G between the non-edge portion of the upper surface of the secondelectrode E2 and the non-edge portion of the rear surface of the lowerstructure 1100.

Particularly, the gap G before occurrence of the force touch is G1, andthe gap G after occurrence of the touch force is G2, which is smallerthan G1.

Such a decrease of the gap G from G1 to G2, before and after occurrenceof a force touch, changes the second capacitance C2 and enablesrecognition of the force touch.

The gap structure unit 1000 of FIG. 13 can increase the gap change anddoes not require modification of existing structures, such as thedisplay panel 110 and the lower structure 1100, making it possible toeasily implement a touch system 100 capable of efficient force touchsensing.

Referring to FIG. 14, the gap structure unit 1000 may include a baseplate 1310 made of a substrate or a film, an elastic sheet 1400positioned between the upper surface of a second electrode E2, which ispositioned on the base plate 1310, and the rear surface of a lowerstructure 1100, and the like.

The elastic sheet 1400 may be attached, bonded, or coated on the rearsurface of the lower structure 1100.

Referring to FIG. 14, when a force touch occurs, the upper cover 1240,the display panel 110, the lower structure 1100, and the like receive adownward force. Accordingly, the touch force of the touch changes thethickness of the elastic sheet, and the size of the G between the uppersurface of the second electrode E2 and the rear surface of the lowerstructure 1100 may change as a result.

Particularly, the gap G before occurrence of the force touch is G1, andthe gap G after occurrence of the touch force is G2, which is smallerthan G1.

Such a decrease of the gap G from G1 to G2, before and after occurrenceof a force touch, changes the second capacitance C2 and enablesrecognition of the force touch.

The gap structure unit 1000 of FIG. 14 can be made thinner, and does notrequire modification of existing structures, such as the display panel110 and the lower structure 1100, making it possible to easily implementa touch system 100 capable of efficient force touch sensing with nosignificant change in size of the in-cell touch type display device.

Referring to FIG. 15, the gap structure unit 1000 may include an upperfilm 1520 positioned on the rear surface of a lower structure 1100, alower film 1510 facing the upper film 1520, a bonding agent 1530 bondedto the rear surface edge of the upper film 1520 and to the upper surfaceedge of the lower film 1510, and the like.

Referring to FIG. 15, a second electrode E2 may be positioned in aninternal space provided by spacing between the non-edge portion of therear surface of the upper film 1520 and the non-edge portion of theupper surface of the lower film 1510.

Referring to FIG. 15, a spacer 1540 may exist on the upper surface ofthe second electrode E2. When a force touch occurs, the upper cover1240, the display panel 110, the lower structure 1100, and the likereceive a downward force. Accordingly, the size of the G between theupper surface of the second electrode E2 and the rear surface of theupper film 1520 may change according to the touch force of the touch.

Particularly, the gap G before occurrence of the force touch is G1, andthe gap G after occurrence of the touch force is G2, which is smallerthan G1. Such a decrease of the gap G from G1 to G2, before and afteroccurrence of a force touch, changes the second capacitance C2 andenables recognition of the force touch.

The spacer 1540 may be made of resilient material so that it can bedeformed when pressed down by the upper film 1520 and can recover itsshape when the upper film 1520 no longer exerts force on the spacer1540. The spacer 1540 prevents the upper film 1520 (or the lowerstructure 1100) from coming into direct contact with the secondelectrode E2 and also prevents the second electrode E2 from deformingeven when external force is applied through the upper cover 1240. Thespacer 1540 may be made of conductive or non-conductive material.

The gap structure unit 1000 of FIG. 15 is implemented in a module typesuch that, without modifying existing structures such as the displaypanel 110, the lower structure 1100, and the like, the module-type gapstructure unit 1000 can be attached beneath the lower structure 1100.This is advantageous in that the gap structure unit 1000 can be includedin the in-cell touch type display device.

Referring to FIG. 16, the gap structure unit 1000 may include an elasticfilm 1600 positioned between the upper surface of a second electrode E2and the rear surface of a lower structure 1100, and the like. When aforce touch occurs, the upper cover 1240, the display panel 110, thelower structure 1100, and the like receive a downward force.Accordingly, the touch force of the touch changes the thickness of theelastic film, and the size of the G between the upper surface of thesecond electrode E2 and the rear surface of the lower structure 1100 maychange as a result.

Particularly, the gap G before occurrence of the force touch is G1, andthe gap G after occurrence of the touch force is G2, which is smallerthan G1. Such a decrease of the gap G from G1 to G2, before and afteroccurrence of a force touch, changes the second capacitance C2 andenables recognition of the force touch.

The gap structure unit 1000 of FIG. 16 has a small thickness andtherefore can implement a touch system 100 capable of force touchsensing without increasing the size of the in-cell touch type displaydevice.

Referring to FIG. 17, the gap structure unit 1000 may include an innerpattern 1700 embedded in a lower structure 1100. When a force touchoccurs, the upper cover 1240, the display panel 110, the lower structure1100, and the like receive a downward force. Accordingly, the innerpattern 1700, which is inside the lower structure 1100, also receivesthe force, and the touch force of the touch may change size of the gap Gbetween the upper surface of the second electrode E2, which ispositioned beneath the lower structure 1100, and the inner pattern.

The inner pattern 1700 may be made of resilient material so that it canbe deformed when pressed down and can recover its shape when externalforce is no longer applied. The internal pattern 1700 prevents theexternal force from being transferred to the second electrode E2 andthereby prevents the second electrode E2 from being deformed by theexternal force. The internal pattern 1700 may be made of conductive ornon-conductive material.

Particularly, the gap G before occurrence of the force touch in theinternal pattern 1700 is G1, and the gap in the internal pattern 1700after occurrence of the touch force is G2, which is smaller than G1.Such a decrease of the gap G from G1 to G2, before and after occurrenceof a force touch, changes the second capacitance C2 and enablesrecognition of the force touch.

The gap structure unit 1000 of FIG. 17 is included inside the lowerstructure 1100 and therefore can implement a touch system 100 capable offorce touch sensing without changing the size of the in-cell touch typedisplay device.

FIG. 18 is a block diagram of a touch circuit 120 according to thepresent embodiments. Referring to FIG. 18, a touch circuit 120 accordingto the present embodiments may include a first electrode driving unit1810 configured to output a first electrode driving signal DS1, which isto be sequentially applied to each of multiple first electrodes E1during touch driving, a second electrode driving unit 1820 configured tooutput a second electrode driving signal DS2, which is to be applied toa second electrode E2 during touch driving, and the like.

Use of the touch circuit 120 according to the present embodimentsenables performing of first electrode driving and second electrodedriving in the same touch driving process; as a result, sensingregarding whether a touch occurs or not and regarding the touchcoordinate and touch force sensing can be performed within a shorterperiod of time.

The second electrode driving signal DS2 and the first electrode drivingsignal DS1 may have the same phase. That is, the second electrodedriving signal DS2 and the first electrode driving signal DS1 may havean equiphase relationship.

The second electrode driving signal DS2 and the first electrode drivingsignal DS1 may have a phase difference of 180 degrees. That is, thesecond electrode driving signal DS2 and the first electrode drivingsignal DS1 may have a reverse-phase relationship.

The second electrode driving signal DS2 may have a signal amplitudelarger than that of the first electrode driving signal DS1.

On the other hand, referring to FIG. 18, the touch circuit 120 accordingto the present embodiments may further include a sensing unit 1830configured such that during touch driving, a first electrode drivingsignal DS1 is successively applied to the multiple first electrodes E1,a second electrode driving signal DS2 is applied to the second electrodeE2, and the sensing unit 1830 senses a touch on the basis of signalsreceived from the multiple first electrodes E1, respectively.

The sensing unit 1830 can calculate the coordinate of the touch, on thebasis of signals received from the multiple first electrodes E1,respectively, and can sense the amount of charging or voltage, whichfollows the change in size of the gap G between the multiple firstelectrodes E1 and the second electrode E2 (G1−>G2), thereby recognizingthe touch force of the touch.

The sensing unit 1830 may sense the touch coordinate and the touch forcein a self capacitance-based sensing type, among capacitance-based touchsensing types.

Referring to FIG. 18, the touch system 120 according to the presentembodiments may further include a second electrode driving signalgeneration unit 130 configured to generate a second electrode drivingsignal DS2, which corresponds to the first electrode driving signal DS1.

As described above, the touch circuit 120 includes a second electrodedriving signal generation unit 130 such that, through the touch circuit120, a second electrode driving signal DS2 can be generated easily andefficiently through processing such as generating a first electrodedriving signal DS1 and shifting the level regarding the first electrodedriving signal DS1 or reversing the phase, for example.

FIG. 19 to FIG. 21 are diagrams illustrating examples of implementationof an in-cell touch type display device and a touch circuit 120according to the present embodiments. As illustrated in FIG. 19, thetouch circuit 120 may be included outside a data driver 1900. Asillustrated in FIG. 20, the touch circuit 120 may be included inside thedata driver 1900, which is implemented in a chip type. As illustrated inFIG. 21, the touch circuit 120 may be included in a chip-type displaydriver 2100 together with a data driver 1900.

As described above, various types of touch circuits 120 can beimplemented in various manners. Particularly, when the touch circuit 120is implemented by including the same in a chip-type data driver 1900 ora display driver 2100, the number of chips mounted or connected to thedisplay panel 110 can be reduced.

A display driver 2100, which includes a touch circuit 120 and a datadriver 1900, and which is implemented in a chip type, will hereinafterbe described briefly.

FIG. 22 is a block diagram of a display driver 2100 according to thepresent embodiments. FIG. 23 is a diagram illustrating data driving by adata driving circuit 2210 included in a display driver 2100 according tothe present embodiments. FIG. 24 is a diagram illustrating touch driving(first electrode driving and second electrode driving) by a touchcircuit 120 included in a display driver 2100 according to the presentembodiments.

Referring to FIG. 22, the display driver 2100 according to the presentembodiments includes a data driving circuit 2210 configured to output adata voltage to multiple data lines during display driving, a touchcircuit 120 configured to output a first electrode driving signal DS1,which is to be successively applied to multiple first electrodes E1arranged on the display panel 110, during touch driving and configuredto output a second electrode driving signal DS2, which is to be appliedto a second electrode E2 arranged outside the display panel 110, and thelike.

Use of a one chip-type display driver 2100, which includes a datadriving circuit 2210 and a touch circuit 120 as described above, canreduce the number of chips mounted or connected to the display panel110.

Referring to FIG. 22, the display driver 2100 according to the presentembodiments may further include a second electrode driving signalgeneration unit 130 configured to generate a second electrode drivingsignal DS2, which corresponds to the first electrode driving signal DS1.

As described above, the display driver 2100 includes a second electrodedriving signal generation unit 130 such that a second electrode drivingsignal DS2 can be generated easily and efficiently through processingsuch as generating a first electrode driving signal DS1 and shifting thelevel regarding the first electrode driving signal DS1 or reversing thephase, for example.

Referring to FIG. 23, the data driving circuit 2210 may supply a datavoltage for image display, to multiple data lines DL arranged on thedisplay panel 110 during display driving in a display driving modeperiod.

The data driving circuit 2210 corresponds to a data driver 1900.

Referring to FIG. 24, signals lines SL may be arranged on the displaypanel 110 so as to connect the multiple first electrodes E1 to the touchcircuit 120, respectively.

The touch circuit 120 successively supplies a first electrode drivingsignal DS1 to the multiple first electrodes E1 during touch driving in atouch mode period.

To this end, one or more multiplexers (not illustrated) may be providedinside or outside the display driver 2100 so as to electrically connectat least one of the multiple signal lines SL to the touch circuit 120.

Accordingly, at a specific point of time, a first electrode drivingsignal DS1 is applied to at least one first electrode E1.

While a first electrode driving signal DS1 is successively applied tothe multiple first electrodes E1, and a second electrode driving signalDS2 may be applied to the second electrode E2.

Referring to FIG. 24, the second electrode driving signal generationunit 130 may generate a second electrode driving signal DS2 on the basisof the first electrode driving signal DS1 generated and output from thetouch circuit 120.

The two kinds of signals applied during touch driving, i.e. the secondelectrode driving signal DS2 and the first electrode driving signal DS1,may have the same phase. That is, the second electrode driving signalDS2 and the first electrode driving signal DS1 may have an equiphaserelationship.

The second electrode driving signal DS2 and the first electrode drivingsignal DS1 may have a phase difference of 180 degrees. That is, thesecond electrode driving signal DS2 and the first electrode drivingsignal DS1 may have a reverse-phase relationship.

The second electrode driving signal DS2 may have a signal amplitudelarger than that of the first electrode driving signal DS1.

The touch circuit 120 included in the display driver 2100 may beconfigured such that during touch driving, a first electrode drivingsignal DS1 is successively applied to the multiple first electrodes E1,a second electrode driving signal DS2 is applied to the second electrodeE2, and the touch circuit 120 senses a touch on the basis of signalsreceived from the multiple first electrodes E1, respectively.

The touch circuit 120 can calculate the coordinate of the touch, on thebasis of signals received from the multiple first electrodes E1,respectively, and can sense the amount of charging or voltage, whichfollows the change in size of the gap G between the multiple firstelectrodes E1 and the second electrode E2, thereby recognizing the touchforce of the touch.

Therefore, it is possible to provide a display driver 2100 not onlycapable of data driving for image display, but also capable of touchcoordinate sensing and force sensing through the same.

On the other hand, the multiple first electrodes E1 may be mode-sharingelectrodes that can be used as display driving electrodes in a displaydriving mode.

Therefore, the display driver 2100 may further include a multiplexer(not illustrated) configured to output a common voltage, which is to beapplied to the multiple first electrodes E1 during display driving, andconfigured to output a first electrode driving signal DS1, which is tobe successively applied to the multiple first electrodes E1 during touchdriving.

A method for driving the in-cell touch type display device according tothe present embodiments, which has been described above, will now bedescribed briefly.

FIG. 25 is a flowchart of a method for driving an in-cell touch typedisplay device according to the present embodiments.

Referring to FIG. 25, the method for driving an in-cell touch typedisplay device according to the present embodiments includes a step(S2510) of successively applying a first electrode driving signal DS1 tomultiple first electrodes E1, which are embedded in a display panel 110,and applying a second electrode driving signal DS2 to a second electrodeE2, which is positioned outside the display panel 110, during touchdriving, a step (S2520) of sensing a touch on the basis of signalsreceived from the multiple first electrodes E1, respectively, and thelike.

In the above-mentioned step S2520, the coordinate of the touch can becalculated on the basis of signals received from the multiple firstelectrodes E1, respectively, and the amount of charging or voltage,which follows the change in size of the gap G between the multiple firstelectrodes E1 and the second electrode E2, can be sensed, therebyrecognizing the touch force of the touch.

The above-mentioned method for driving an in-cell touch type displaydevice according to the present embodiments, when employed, can proceedwith first electrode driving and second electrode driving in the sametouch driving process and therefore can perform sensing related towhether a touch has occurred or not and the coordinate of the touch andtouch force sensing within a shorter period of time compared with a casein which the first electrode driving and the second electrode drivingproceed separately through different driving processes.

The in-cell touch type display device 100 according to the presentembodiments, described above, may include multiple first electrodes E1embedded in a display panel 110, a second electrode E2 positionedoutside (for example, beneath) the display panel 110, a touch forcesensing circuit configured to drive the multiple first electrodes E1,which are embedded in the display panel 110, and the second electrodeE2, which is positioned outside the display panel 110, together duringone touch driving period and configured to sense a touch force appliedto the display panel 110, and the like.

In this regard, the touch force sensing circuit may be a touch circuit120 or a display driver 2100, for example.

The present embodiments, described above, can provide an in-cell touchtype display device, a touch circuit 120, a display driver 2100, and anin-cell touch type display device driving method, which can not onlysense the coordinate (position) of a touch generated by the user, butalso sense the touch force, with which the user presses the screenduring the touch, in order to provide various functions in varioustypes.

The present embodiments can provide an in-cell touch type displaydevice, a touch circuit 120, a display driver 2100, and an in-cell touchtype display device driving method, which can sense a touch force, withwhich the user presses the screen during a touch, using an existingtouch structure, without any separate pressure sensor or the like.

The present embodiments can provide an in-cell touch type displaydevice, a touch circuit 120, a display driver 2100, and an in-cell touchtype display device driving method, which enable simultaneous proceedingof driving for sensing a touch coordinate and driving for sensing atouch force, during a touch driving process.

The present embodiments can provide an in-cell touch type displaydevice, a touch circuit 120, a display driver 2100, and an in-cell touchtype display device driving method, which can recognize the position ofoccurrence of a touch force, i.e. a force with which the user pressesthe screen, through simultaneous proceeding of first electrode drivingand second electrode driving during touch driving.

The present embodiments can provide an in-cell touch type displaydevice, a touch circuit 120, a display driver 2100, and an in-cell touchtype display device driving method, which can accurately distinguishbetween a soft touch, i.e. the force with which the user's touch pressesthe screen does not exist or is equal to or less than a predeterminedlevel, and a force touch, i.e. the force with which the user's touchpresses the screen exists or exceeds the predetermined level.

The present embodiments can provide an in-cell touch type displaydevice, a touch circuit 120, a display driver 2100, and an in-cell touchtype display driving method, which enable sensing of a touch force bysimultaneously using first electrodes E1, which are provided to sense atouch coordinate, together with a second electrode FS.

The above description and the accompanying drawings provide an exampleof the technical idea of the present invention for illustrative purposesonly. Those having ordinary knowledge in the technical field, to whichthe present invention pertains, will appreciate that variousmodifications and changes in form, such as combination, separation,substitution, and change of a configuration, are possible withoutdeparting from the essential features of the present invention.Therefore, the embodiments disclosed in the present invention areintended to illustrate the scope of the technical idea of the presentinvention, and the scope of the present invention is not limited by theembodiment. The scope of the present invention shall be construed on thebasis of the accompanying claims in such a manner that all of thetechnical ideas included within the scope equivalent to the claimsbelong to the present invention.

What is claimed is:
 1. An in-cell touch type display device comprising:a plurality of first electrodes embedded in a display panel; at leastone second electrode outside the display panel and capacitively coupledto each of the first electrodes; and a touch circuit coupled to thefirst electrodes and the at least one second electrode, the touchcircuit configured to: apply a first voltage signal to each of the firstelectrodes, apply a second voltage signal to the at least one secondelectrode, and detect touch force on the display panel by processing asensing signal representing a voltage level at each of the firstelectrodes, responsive to applying the first voltage signal and thesecond voltage signal, wherein the first voltage signal and the secondvoltage signals have different voltage levels.
 2. The in-cell touch typedisplay device of claim 1, wherein the first signal and the secondsignal are applied during a touch driving period within a frame period.3. The in-cell touch type display device of claim 1, wherein the touchcircuit is further configured to determine a coordinate of a touch byprocessing sensing signals from the first electrodes.
 4. The in-celltouch type display device of claim 1, wherein the sensing signal is of afirst voltage level responsive to the display panel receiving a touch ofa first touch force and the sensing signal is of a second voltage levelresponsive to the display panel receiving a touch of a second touchforce weaker than the first touch force, the first voltage level higherthan the second voltage level.
 5. The in-cell touch type display deviceof claim 1, wherein the touch circuit is configured to determine thetouch as a first type of touch responsive to a voltage level of thesensing signal not exceeding a reference voltage and determine the touchas a second type of touch responsive to the voltage level of the sensingsignal exceeing the reference voltage.
 6. The in-cell touch type displaydevice of claim 1, wherein each of the first electrodes and the at leastone second electrode are separated by a distance that changes accordingto magnitude of touch force on the display panel, the change in thedistance causing change in the sensing signal.
 7. The in-cell touch typedisplay device of claim 6, wherein air or dielectric material is betweenthe first electrodes and the at least one second electrode.
 8. Thein-cell touch type display device of claim 1, further comprising astructure configured to mount the display panel, the at least one secondelectrode placed beneath or inside the structure.
 9. The in-cell touchtype display device of claim 1, further comprising a gap structure unitconfigured to set a distance between the first electrodes and the atleast one second electrode when the touch force is not applied to thedisplay panel, the distance changing responsive the touch force appliedto the display panel.
 10. The in-cell touch type display device of claim9, wherein the gap structure unit comprises: a base plate on which theat least one second electrode is mounted; and a spacer elastic patternbetween edges of an upper surface of the at least one second electrodeand edges of a rear surface of a lower structure.
 11. The in-cell touchtype display device of claim 9, wherein the gap structure unitcomprises: a base plate on which the at least one second electrode ismounted; and an elastic sheet between an upper surface of the at leastone second electrode and a rear surface of a lower structure.
 12. Thein-cell touch type display device of claim 9, wherein the gap structureunit comprises: an upper film on a rear surface of a lower structure; alower film facing the upper film; and a bonding agent bonding edges of arear surface of the upper film to an upper surface of the lower film.13. The in-cell touch type display device of claim 9, wherein the gapstructure unit comprises an elastic film between an upper surface of theat least one second electrode and a rear surface of a lower structure.14. The in-cell touch type display device of claim 9, wherein the gapstructure unit comprises an inner pattern embedded in a lower structure.15. The in-cell touch type display device of claim 14, wherein the lowerstructure is a back light unit of the display panel.
 16. The in-celltouch type display device of claim 2, wherein the first electrodes areapplied with a common voltage during a display driving period of theframe period.
 17. The in-cell touch type display device of claim 1,wherein the touch circuit is included inside a data driver forgenerating signals for operating pixels in the display panel.
 18. Thein-cell touch type display device of claim 1, wherein the touch circuitcomprises: a first switch turned on or off to selectively connect eachof the first electrodes to a first reference voltage; and a secondswitch turned on or off to selectively connect each of the firstelectrodes to a second reference voltage lower than the first referencevoltage, the first signal changing between the first reference voltageand the second reference voltage.
 19. The in-cell touch type displaydevice of claim 18, wherein the touch circuit further comprises: a thirdswitch turned on or off to selectively connect the at least one secondelectrode to a third reference voltage; and a fourth switch turned on oroff to selectively connect the at least one second electrode to a fourthreference voltage lower than the third reference voltage, the secondsignal changing between the third reference voltage and the fourthreference voltage.
 20. The in-cell touch type display device of claim 1,wherein the touch circuit comprises: a signal path connected to each ofthe first electrodes; a resistor connected to the signal path; acapacitor having a first node connected to the resistor; an operationalamplifier having an inverted input connected to the resistor and anoutput connected to a second node of the capacitor; an analog-to-digitalconverter configured to receive an output signal from the output of theoperational amplifier and convert the output signal to a digital signal;and a processor configured to process the digital signal to detect thetouch force.
 21. A touch circuit comprising: a first electrode drivingcircuit configured to output a first signal to each of a plurality offirst electrodes embedded in a display panel; a second electrode drivingcircuit configured to output a second signal to at least one secondelectrode outside the display panel; and a detection circuit configuredto detect touch force on the display panel by processing a sensingsignal representing a voltage level at each of the first electrodes,responsive to applying the first voltage signal and the second voltagesignal, wherein the first signal and the second signal have differentvoltage levels.
 22. The touch circuit of claim 21, wherein the firstsignal and the second signal are applied during a touch driving periodwithin a frame period.
 23. The touch circuit of claim 21, wherein thesensing signal is of a first voltage level responsive to the displaypanel receiving a touch of a first touch force and the sensing signal isof a second voltage level responsive to the display panel receiving atouch of a second touch force weaker than the first touch force, thefirst voltage level higher than the second voltage level.